KR102377440B1 - Improved resource allocation for device to device (d2d) communication - Google Patents

Abstract

The present invention relates to a method for allocating radio resources to a transmitting terminal for performing direct communication transmission through a direct link connection. The transmitting terminal receives the system information broadcast from the base station, and the system information broadcast includes information on a temporary transmission radio resource pool indicating radio resources for performing direct communication transmission, and the temporary radio resource pool is determined by the transmitting terminal. Contains configuration information for the resource pool to limit the amount of available time.

Description

IMPROVED RESOURCE ALLOCATION FOR DEVICE TO DEVICE (D2D) COMMUNICATION

The present disclosure relates to a method for allocating radio resources to a transmitting terminal for performing direct communication transmission through a direct link connection with a receiving terminal. The present disclosure also provides a transmitting terminal and a base station for participating in the method described herein.

Long Term Evolution (LTE)

Third-generation mobile systems (3G) based on WCDMA radio-access technology are being widely deployed throughout the world. The first step in enhancing or advancing these technologies is to introduce high-speed downlink packet access (HSDPA) and enhanced uplinks (also referred to as high-speed uplink packet access (HSUPA)), making them highly competitive radio-access technologies. entails doing

To further prepare for increasing user demand and to be competitive with new radio access technologies, 3GPP introduced a new mobile communication system referred to as Long Term Evolution (LTE). LTE is designed to meet carrier demands for high-speed data and media transmission, as well as high-capacity voice support over the next decade. The ability to provide high bit rates is a key metric for LTE.

The Work Item (WI) specification on Long-Term Evolution (LTE), referred to as evolved UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN), was finalized as Release 8 (LTE Rel.8). The LTE system represents an efficient packet-based radio access and radio access network that provides full IP-based functionality with low latency and low cost. In LTE, a number of scalable transmission bandwidths, such as 1.4, 3.0, 5.0, 10.0, 15.0 and 20.0 MHz, are specified to achieve flexible system deployment using a given spectrum. In the downlink, orthogonal frequency division multiplexing (OFDM) based radio access was adopted, which, due to the low symbol rate, use of cyclic prefix (CP) and the affinity of OFDM for different transmission bandwidth arrangements, multipath interference (MPI) ) due to the inherent immunity of OFDM to In the uplink, single-carrier frequency division multiple access (SC-FDMA) based radio access is adopted, which takes into account the limited transmit power of user equipment (UE), provisioning wide area coverage rather than improvement in peak data rate. Because this has been prioritized. In LTE Rel.8/9, many core packet radio access technologies are used, including multiple input multiple output (MIMO) channel transmission technology, and a very efficient control signaling structure is achieved.

LTE architecture

The overall architecture is shown in FIG. 1 , and a more detailed representation of the E-UTRAN architecture is given in FIG. 2 . E-UTRAN consists of eNodeBs that provide E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol termination towards user equipment (UE). The eNodeB (eNB) hosts the Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Control Protocol (PDCP) layers, and the PDCP layer includes user-plane header-compression and encryption includes the functions of The eNodeB also provides a radio resource control (RRC) function corresponding to the control plane. The eNodeB provides radio resource management, admission control, scheduling, enforcement of negotiated uplink quality of service (QoS), cell information broadcast, encryption/decryption of user and control plane data, and of downlink/uplink user plane packet headers. It performs many functions including compression/decompression. The eNodeBs are interconnected with each other using an X2 interface.

The eNodeB is also connected to the Evolved Packet Core (EPC) using the S1 interface, more specifically to the Mobility Management Entity (MME) using the S1-MME and to the Serving Gateway (SGW) using the S1-U. . The S1 interface supports a many-to-many relationship between the MME/Serving Gateway and the eNodeB. The SGW routes and forwards user data packets, while acting as a mobility anchor for the user plane during inter-eNodeB handover and as an anchor for mobility between LTE and other 3GPP technologies (terminating the S4 interface and 2G/ relay traffic between the 3G system and the PDN GW). For idle state user equipment, the SGW terminates the downlink data path and triggers paging when the downlink data arrives at the user equipment. The SGW manages and stores the user equipment context, for example, parameters of IP bearer service, and network internal routing information. The SGW also performs replication of user traffic in case of legitimate interception.

The MME is the key control-node for the LTE access-network. The MME is responsible for idle mode user equipment tracking and paging procedures including retransmissions. The MME is involved in the bearer activation/deactivation process, and is also responsible for selecting the SGW for the user equipment upon initial connection and during intra-LTE handover involving core network (CN) node relocation. The MME is responsible for authenticating the user (by interacting with the HSS). NAS (Non-Access Stratum) signaling is terminated at the MME, and is also responsible for the creation and assignment of temporary identities for user equipment. NAS signaling checks the user equipment's authorization to camp on the service provider's Public Land Mobile Network (PLMN), and enforces user equipment roaming restrictions. The MME is the endpoint of the network for encryption/integrity protection for NAS signaling, and handles security key management. Legal interception of signaling is also supported by the MME. The MME also provides control plane functions for mobility between LTE and 2G/3G access networks using the S3 interface terminating at the MME from the SGSN. The MME also terminates the S6a interface towards the home HSS for roaming user equipment.

Component carrier structure in LTE

개의 서브캐리어 상에서 송신되는 다수의 변조 심볼로 구성된다.The downlink component carrier of the 3GPP LTE system is subdivided in the time-frequency domain in so-called subframes. In 3GPP LTE, each subframe is divided into two downlink slots as shown in FIG. 3 , and the first downlink slot includes a control channel region (PDCCH region) within the first OFDM symbol. Each subframe consists of a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8)), each OFDM symbol spanning the entire bandwidth of a component carrier. Thus, each OFDM symbol, as also shown in FIG. 4 , is

It consists of a number of modulation symbols transmitted on subcarriers.

개의 연속적인 OFDM 심볼(예를 들어, 7개의 OFDM 심볼) 및 주파수 도메인에서

개의 연속적인 서브캐리어(예를 들어, 컴포넌트 캐리어에 대한 12개의 서브캐리어)로서 정의된다. 따라서, 3GPP LTE(릴리스 8)에서, 물리 자원 블록은, 시간 도메인에서 하나의 슬롯 및 주파수 도메인에서 180 kHz에 대응하는

개의 자원 엘리먼트로 구성된다(다운링크 자원 그리드에 대한 추가적인 세부사항의 경우, 예를 들어, http://www.3gpp.org에서 입수가능하고 참조로 본원에 통합된 3GPP TS 36.211, "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)", 섹션 6.2를 참조한다).For example, assuming a multi-carrier communication system using OFDM, for example, as used in 3GPP Long Term Evolution (LTE), the minimum unit of resources that can be allocated by the scheduler is one "resource"block". A physical resource block (PRB) is, as illustrated in FIG. 4 , in the time domain

consecutive OFDM symbols (eg, 7 OFDM symbols) and in the frequency domain

n contiguous subcarriers (eg, 12 subcarriers for a component carrier). Thus, in 3GPP LTE (Release 8), a physical resource block corresponds to one slot in the time domain and 180 kHz in the frequency domain.

(for additional details on the downlink resource grid, for example, 3GPP TS 36.211, “Evolved Universal Terrestrial, available at http://www.3gpp.org and incorporated herein by reference) Radio Access (E-UTRA); see Physical Channels and Modulation (Release 8)", section 6.2).

개의 연속적인 서브캐리어와 동등한 시간-주파수 자원은 "자원 블록 쌍" 또는 동등하게 "RB 쌍" 또는 "PRB 쌍"으로 지칭된다.One subframe includes two slots, so that when a so-called "regular" cyclic prefix (CP) is used, there are 14 OFDM symbols in a subframe, and when a so-called "extended" CP is used, in a subframe There are 12 OFDM symbols. For the sake of terminology, below, the same over the entire subframe

A time-frequency resource equal to n consecutive subcarriers is referred to as a “resource block pair” or equivalently a “RB pair” or “PRB pair”.

The term “component carrier” refers to a combination of several resource blocks in the frequency domain. In future releases of LTE, the term “component carrier” will be deprecated; Instead, the term is changed to “cell”, which refers to a combination of downlink and optionally uplink resources. The connection between the carrier frequency of the downlink resource and the carrier frequency of the uplink resource is indicated in system information transmitted on the downlink resource.

Similar assumptions for component carrier structure also apply in future releases.

Carrier aggregation in LTE-A for wider bandwidth support

The frequency spectrum for IMT-Advanced was determined at the World Radiocommunication Conference 2007 (WRC-07). Although the overall frequency spectrum for IMT-Advanced has been determined, the actual usable frequency bandwidth is different for each region or country. However, after the decision on the available frequency spectrum outline, the standardization of the air interface started in the 3rd Generation Partnership Project (3GPP). At the 3GPP TSG RAN #39 meeting, the study item description for "Further Advancements for E-UTRA (LTE-Advanced)" was approved. This study article covers the technical components considered for the advancement of E-UTRA, for example to meet the requirements for IMT-Advanced.

The bandwidth that the LTE-Advanced system can support is 100 MHz, while the LTE system can support only 20 MHz. Recently, the shortage of radio spectrum has become a bottleneck for the development of radio networks, and as a result, it is difficult to find a sufficiently wide spectrum band for the LTE-Advanced system. As a result, it is urgent to find a way to acquire a wider radio spectrum band, and a possible answer is a carrier aggregation function.

In carrier aggregation, two or more component carriers (component carriers) are aggregated to support a wider transmission bandwidth up to 100 MHz. Some cells in the LTE system are aggregated into one wider channel in the LTE-Advanced system, wide enough for 100 MHz, even if these cells are in different frequency bands in LTE

All component carriers may be configured to be compatible with LTE Release 8/9, at least if the aggregated number of component carriers in the uplink and downlink is the same. Not all component carriers aggregated by user equipment may necessarily be compatible with Release 8/9. To avoid Rel-8/9 user equipment camping on component carriers, existing mechanisms (eg blocking) may be used.

User equipment may simultaneously receive or transmit one or multiple component carriers (corresponding to multiple serving cells) according to its capabilities. LTE-A Release 10 user equipment with receive and/or transmit capability for carrier aggregation may simultaneously receive and/or transmit over multiple serving cells, while LTE Release 8/9 user equipment is capable of receiving and/or transmitting component carriers According to the release 8/9 specification, it can receive and transmit only through a single serving cell.

Carrier aggregation is supported for both contiguous and non-contiguous component carriers, each component carrier limited to a maximum of 110 resource blocks in the frequency domain using 3GPP LTE (Release 8/9) numerology .

It is possible to configure 3GPP LTE-A (Release 10) compatible user equipment to aggregate a different number of component carriers originating from the same eNodeB (base station), possibly of different bandwidths in the uplink and downlink. The number of downlink component carriers that can be configured depends on the downlink aggregation capability of the UE. Conversely, the number of uplink component carriers that can be configured depends on the uplink aggregation capability of the UE. It may not be possible to configure a mobile terminal to have more uplink component carriers than downlink component carriers.

In a typical TDD deployment, the number of component carriers and the bandwidth of each component carrier in the uplink and downlink are the same. Component carriers originating from the same eNodeB do not need to provide the same coverage.

The spacing between center frequencies of successively aggregated component carriers will be multiples of 300 kHz. This is to be compatible with the 100 kHz frequency raster of 3GPP LTE (Release 8/9), while at the same time preserving the orthogonality of subcarriers with 15 kHz spacing. Depending on the aggregation scenario, the n x 300 kHz spacing can be facilitated by inserting a small number of unused subcarriers between successive component carriers.

The nature of the aggregation of multiple carriers is exposed only up to the MAC layer. For both the uplink and downlink, there is one HARQ entity required in the MAC for each aggregated component carrier. There is at most one transport block per component carrier (in the absence of SU-MIMO in the case of uplink). Transport blocks and potential HARQ retransmissions of transport blocks need to be mapped on the same component carrier.

A layer 2 structure with activated carrier aggregation is shown in FIGS. 5 and 6 for the downlink and uplink, respectively.

When carrier aggregation is configured, the mobile terminal has only one RRC connection with the network. In RRC connection establishment/re-establishment, one cell provides secure input (one ECGI, one PCI and one ARFCN) and no access layer mobility information (eg TAI), similar to LTE release 8/9 . After RRC connection establishment/re-establishment, the component carrier corresponding to that cell is referred to as a downlink primary cell (PCell). There is always one and only one downlink PCell (DL PCell) and one uplink PCell (UL PCell) configured per user equipment in connected state. Within the configured set of component carriers, other cells are referred to as secondary cells (SCells); The carriers of the SCell are a downlink secondary component carrier (DL SCC) and an uplink secondary component carrier (UL SCC).

Addition and removal as well as configuration and reconfiguration of component carriers may be performed by RRC. Activation and deactivation are done through the MAC control element. In intra-LTE handover, RRC may also add, remove or reconfigure SCells for use in target cells. When adding a new SCell, dedicated RRC signaling is used to transmit system information of the SCell, and this information is essential for transmission/reception (similar to the case of handover in Release-8/9).

When user equipment is configured by carrier aggregation, there is always an active pair of uplink and downlink component carriers. The downlink component carrier of the pair may also be referred to as a 'DL anchor carrier'. The same applies to the uplink as well.

When carrier aggregation is configured, user equipment can be scheduled on multiple component carriers at the same time, but at most one random access procedure will be in progress at any time. Cross-carrier scheduling allows the PDCCH of a component carrier to schedule resources on other component carriers. To this end, a component carrier identification field called CIF is introduced in each DCI format.

The connection between the uplink and downlink component carriers makes it possible to identify the uplink component carrier to which a grant applies in the absence of any cross-carrier scheduling. The connection of the downlink component carrier to the uplink component carrier does not necessarily have to be one to one. That is, more than one downlink component carrier may be linked to the same uplink component carrier. At the same time, the downlink component carrier can be linked to only one uplink component carrier.

LTE RRC Status

LTE is based on only two main states: “RRC_IDLE” and “RRC_CONNECTED”.

In RRC_IDLE, the radio is not active, but an ID is assigned and tracked by the network. More specifically, the mobile terminal with RRC_IDLE performs cell selection and reselection, ie, determines which cell to camp on. The cell (re)selection process considers the priority of each applicable frequency, radio link quality and cell condition (ie whether the cell is blocked or reserved) of each applicable radio access technology (RAT). RRC_IDLE The mobile terminal monitors the paging channel to detect an incoming call, and also acquires system information. The system information consists mainly of parameters that allow the network (E-UTRAN) to control the cell (re)selection process and also how the mobile terminal accesses the network. RRC specifies applicable control signaling, ie, paging and system information, for a mobile terminal that is RRC_IDLE. The operation of the mobile terminal in RRC_IDLE is specified in more detail, for example, in TS 36.304, Chapter 4 "General description of Idle mode", incorporated herein by reference.

In RRC_CONNECTED, the mobile terminal has the context and active radio operation of the eNodeB. The E-UTRAN allocates radio resources to mobile terminals to facilitate transmission of (unicast) data over a shared data channel. To support this operation, the mobile terminal monitors the associated control channel used to indicate the dynamic allocation of the shared transmission resource in time and frequency. The mobile terminal not only provides the network with a report of its buffer status and downlink channel quality, but also provides neighbor cell measurement information to enable the E-UTRAN to select the most appropriate cell for the mobile terminal. These measurement reports include cells using different frequencies or RATs. The UE also receives system information mainly consisting of information required to use a transmission channel. A UE with RRC_CONNECTED may be configured to have discontinuous reception (DRX) cycles to extend its battery life. RRC is a protocol that allows E-UTRAN to control UE operation in RRC_CONNECTED.

Various functions of a mobile terminal in the RRC protocol for connected mode, including connected mode, are described in 3GPP TS36.331 Chapter 4 "Functions", which is incorporated herein by reference.

Uplink access scheme for LTE

For uplink transmission, power-efficient user terminal transmission is needed to maximize coverage. Single-carrier transmission combined with FDMA with dynamic bandwidth allocation was chosen as the evolved UTRA uplink transmission scheme. The main reasons for the preference for single-carrier transmission are the lower peak-to-average power ratio (PAPR) compared to multi-carrier signals (OFDMA), and the corresponding improved power-amplifier efficiency and supposed improved coverage ( higher data rate for a given terminal peak power). During each time interval, the Node B allocates a unique time/frequency resource for transmitting user data to the user, ensuring intra-cell orthogonality. Orthogonal access in the uplink ensures increased spectral efficiency by eliminating intra-cell interference. Interference due to multipath propagation is handled at the base station (Node B) and assisted by inserting a cyclic prefix into the transmitted signal.

A basic physical resource used for data transmission consists of a frequency resource of a size BW _grant during a subframe of one time interval to which the coded information bits are mapped, for example, 0.5 ms. It should be noted that a subframe, also referred to as a transmission time interval (TTI), is the minimum time interval for user data transmission. However, by concatenating subframes, it is possible to allocate a frequency resource BW _grant to a user over a time period longer than one TTI.

UL Scheduling Scheme for LTE

The uplink scheme allows both scheduled access (ie, controlled by the eNB) and contention-based access.

For scheduled access, the UE is allocated a specific frequency resource (ie, time/frequency resource) for a specific time for uplink data transmission. However, some time/frequency resources may be allocated for contention-based access. Within these time/frequency resources, the UE can transmit without having to be scheduled first. One scenario in which the UE is doing contention-based access is, for example, random access, ie, when the UE is performing initial access to a cell or when requesting uplink resources.

For scheduled access, the Node B scheduler allocates a unique frequency/time resource to the user for uplink data transmission. More specifically, the scheduler is

· Which UE(s) are allowed to transmit.

· Which physical channel resource (frequency),

Transmission format to be used by the mobile terminal for transmission (Modulation Coding Scheme (MCS))

to decide

The allocation information is signaled to the UE through a scheduling grant transmitted on the L1/L2 control channel. For simplicity, this channel is hereinafter referred to as an uplink grant channel. The scheduling grant message includes at least information about which part of the frequency band the UE is allowed to use, the validity period of the grant, and the transmission format that the UE should use for future uplink transmissions. The shortest valid period is one subframe. Depending on the scheme selected, additional information may also be included in the acknowledgment message. Only “per UE” grants are used to grant the right to transmit on the UL-SCH (ie, there are no per UE per RB grants). Therefore, the UE needs to distribute the allocated resources among radio bearers according to some rules. Unlike in HSUPA, there is no UE-based transport format selection. The eNB determines the transmission format based on some information, for example, the reported scheduling information and QoS information, and the UE must follow the selected transmission format. In HSUPA, the Node B allocates the maximum uplink resource, and the UE selects the actual transmission format for data transmission accordingly.

Since the scheduling of radio resources is the most important function of a shared channel access network for determining the quality of service, in order to allow efficient QoS management, there are a number of requirements that must be met by the UL scheduling scheme for LTE.

· Lack of low priority services should be avoided;

· A clear QoS distinction for radio bearers/services must be supported by the scheduling scheme;

· To allow the eNB scheduler to identify which radio bearer/service data is to be transmitted, UL reporting should allow fine granularity of buffer reporting (eg per radio bearer or per radio bearer group);

• It should be possible to make clear QoS distinctions between services of different users;

• It should be possible to provide a minimum bit rate per radio bearer.

As can be seen from the list above, one essential aspect of the LTE scheduling scheme is to provide a mechanism by which operators can control the partitioning of their aggregated cell capacity among radio bearers of different QoS classes. The QoS class of the radio bearer is identified by the QoS profile of the corresponding SAE bearer that is signaled from the AGW to the eNB as described above. The operator can then allocate a certain amount of its aggregated cell capacity to the aggregated traffic associated with a radio bearer of a certain QoS class. The main purpose of using this class-based approach is to be able to differentiate the handling of packets according to the QoS class to which they belong.

(broadcast) system information structure

In 3GPP terminology, (broadcast) system information is also indicated as BCCH information, that is, it is carried on the broadcast control channel (logic channel) of the radio cell to which the UE is connected (active state) or attached (idle state). Display information.

Generally, system information includes a master information block (MIB) and several system information blocks (SIB). The MIB includes control information for each system information block. Control information associated with each SIB may have the following structure. Each control information associated with the SIB is the location of the SIB on the transport channel over which this information is transmitted relative to a common timing reference (eg, the location in the time-frequency plane for OFDM radio access, i.e., the transmission of each SIB). A specific resource block allocated for ) may be indicated. Additionally, this repeating period of the SIB may be indicated. This repetition period indicates a period in which each SIB is transmitted. The control information may also include a timer value for a timer-based update mechanism, or alternatively a value tag for tag-based update of SIB information.

The table below lists the categorizations and types of system information blocks in the UMTS legacy system as defined in 3GPP TS 25.331, "Radio Resource Control (RRC)", version 12.2.0, section 8.1.1, which is incorporated herein by reference. gives an overview of System information is also defined for the LTE system, details can be found in TS 36.331 v12.2.0 subclause 6.3.1, incorporated herein by reference.

As will be explained in even greater detail in a later section, a device-to-device (D2D) communication technology is underway to be implemented for LTE-Release 12. Among many others, the 3GPP standard is currently in the process of defining a SystemInformationBlock type 18 to contain some information related to ProSe direct communication and discovery. The following definition of SIB18 is taken from change request r2-143565 currently discussed for so far TS 36.331 capturing agreement on ProSe, but has not yet been finalized and should therefore be taken as an example only.

SystemInformationBlockType18 information element

As is clear from the above system information, the field commIdleTxPool containing the subfield commSA-TxResourcePoolCommon indicates a common resource that can be used (in a contention-based manner) by any UE that is receiving SIB18 and is still idle. That is, the network operator can typically define radio resources for all of the UEs, but these are only available while the UE is still idle. As will be introduced later, these radio resources defined by commIdleTxPool are categorized as Mode 2 resources for autonomous use by the UE.

Buffer status report

The buffer status reporting procedure is used to provide the serving eNB with information about the amount of data available for transmission in the UL buffer of the UE. RRC controls BSR reporting by configuring two timers, periodicBSR-timer and retxBSR-timer, and by signaling, for each logical channel, arbitrarily a logicalChannelGroup that assigns a logical channel to the LCG. Additional information on buffer status reporting can be found in 3GPP TS 36.321 subclause 5.4.5, which is incorporated herein by reference.

LTE Device-to-Device (D2D) Proximity Services (ProSe)

Proximity-based applications and services represent recent social-tech trends. The identified areas include commercial services and public safety related services of interest to operators and users. The introduction of Proximity Services (ProSe) capability in LTE will allow the 3GPP industry to serve this developing market, while serving the urgent needs of several public safety communities belonging together with LTE.

Device-to-device (D2D) communication is a technology component for LTE Release 12. Device-to-device (D2D) communication technology allows D2D as an underlay for a cellular network to increase spectral efficiency. For example, if the cellular network is LTE, all data-carrying physical channels use SC-FDMA for D2D signaling.

D2D communication in LTE

D2D communication in LTE focuses on two areas: discovery and communication.

In D2D communication, UEs transmit data signals to each other via a direct link using cellular resources instead of via a base station (BS). D2D users communicate directly while remaining controlled under the BS, ie while at least in the coverage of the eNB. Accordingly, D2D can improve system performance by reusing cellular resources.

D2D is assumed to operate in the uplink LTE spectrum (in the case of FDD) or in the uplink subframe of the coverage provided by the cell (in the case of TDD except when it is out of coverage). Also, D2D transmission/reception does not use full duplex on a given carrier. From an individual UE's point of view, D2D signal reception and LTE uplink transmission on a given carrier do not use full duplex, ie no simultaneous D2D signal reception and LTE UL transmission are possible.

In D2D communication, when one specific UE1 plays the role of transmitting (sending user equipment or transmitting terminal), UE1 transmits data and the other UE2 (receiving user equipment) receives it. UE1 and UE2 may change their transmit and receive roles. The transmission from UE1 may be received by one or more UEs, such as UE2.

For the user plane protocol, part of the discussion in terms of D2D communication is provided below (see also 3GPP TS 36.843 version 12.0.0 section 9.2.2, incorporated herein by reference):

1. PDCP:

· 1:M D2D broadcast communication data (ie IP packets) should be handled as normal user plane data.

Header-compression/decompression of PDCP is applicable for 1:M D2D broadcast communication.

· U-mode is used for header compression in PDCP for D2D broadcast operation for public safety;

· RLC:

· RLC UM is used for 1:M D2D broadcast communication.

· Segmentation and reassembly are supported on L2 by RLC UM.

· The receiving UE needs to maintain at least one RLC UM entity per transmitting peer UE.

· The RLC UM receiver entity does not need to be configured prior to reception of the first RLC UM data unit.

· So far, no need has been identified for RLC AM or RLC TM for D2D communication for user plane data transmission.

· MAC:

· No HARQ feedback is assumed for 1:M D2D broadcast communication.

· The receiving UE needs to know the source ID to identify the receiver RLC UM entity.

· MAC header contains L2 target ID which allows filtering of packets in MAC layer.

· The L2 target ID can be a broadcast, group cast or unicast address.

· L2 Groupcast/Unicast: The L2 target ID carried in the MAC header will allow to discard the received RLC UM PDU even before forwarding it to the RLC receiver entity.

· L2 Broadcast: The receiving UE will process all received RLC PDUs from all transmitters and intend to reassemble the IP packets and forward them to the upper layer.

· The MAC subheader contains the LCID (to distinguish multiple logical channels).

· At least multiplexing/de-multiplexing, priority handling and padding are useful for D2D.

radio resource allocation

From the perspective of a transmitting UE, a proximity service capable UE (ProSe-capable UE) can operate in two modes for resource allocation:

Mode 1 refers to eNB-scheduled resource allocation, where the UE requests transmission resources from the eNB (or Release-10 relay node), and then the eNodeB (or Release-10 relay node) provides direct data and direct control. Schedule the exact resources used by the UE to transmit information (eg, scheduling assignments). The UE needs to be RRC_CONNECTED to transmit data. In particular, the UE sends a scheduling request (D-SR or random access) to the eNB and then a buffer status report (BSR) in the usual way (see also the subsequent chapter “Transmission procedure for D2D communication”). Based on the BSR, the eNB may determine that the UE has data for ProSe direct communication transmission, and may estimate the resources required for the transmission.

On the other hand, mode 2 refers to UE-autonomous resource selection, where the UE selects by itself a resource (time and frequency) for transmitting direct data and direct control information from a resource pool. One resource pool is defined, for example, by the content of SIB18 (as introduced in the previous section), ie by the field commIdleTxPool, and this particular resource pool is broadcast in the cell and then still in RRC_Idle state. It is normally available for all UEs in an in-cell. Alternatively, or additionally, another resource pool may be defined by the eNB and signaled exclusively to the UE, ie using the field commTxResourcePool. Although not yet finalized, the corresponding ProSe information element is currently being standardized for TS 36.331 according to change request r2-143565. Accordingly, the following definitions are to be taken as examples only.

ProseCommConfig information element

This ProSeCommConfig information element may be part of a network response transmitted by the eNB in response to a corresponding request by the UE for which D2D communication is intended. For example, as illustrated in FIG. 16 , when the UE desires to perform D2D communication, the UE may transmit a D2D communication interest indication to the eNB. Then, the D2D communication response may include, for example, the aforementioned ProseCommConfig information element (eg, as part of RRCCommunicationReconfiguration).

In addition, pre-configured radio resources available to UEs outside the coverage of the eNB's cell for D2D transmission of SA or data may also be categorized as mode 2 resources.

Which resource allocation mode the UE intends to use is configurable by the eNB as described above. In addition, which resource allocation mode the UE intends to use for D2D data communication may also depend on the RRC state, ie, RRC_IDLE or RRC_CONNECTED, and the coverage state of the UE, ie, within coverage, out of coverage. A UE is considered to be in coverage if it has a serving cell (ie the UE is RRC_CONNECTED or camping on the cell in RRC_IDLE).

According to the agreement so far in 3GPP (change request to TS 36.300 of R2-143672, see section on resource allocation), the following rules for resource allocation mode apply to the UE:

· When the UE is out of coverage, it can only use mode 2;

· If the UE is within coverage, mode 1 may be used if the eNB configures the UE accordingly.

· If the UE is within coverage, mode 2 may be used if the eNB configures the UE accordingly.

· In the absence of any exceptional conditions, the UE may change from Mode 1 to Mode 2 and vice versa only if configured to make the change by the eNB. When the UE is within coverage, it will only use the mode indicated by the eNB configuration, unless one of the exceptional cases occurs.

· For example, while T311 or T301 is running, the UE considers itself an exceptional condition.

· In the event of an exceptional case, the UE is temporarily allowed to use mode 2 even though it is configured to use mode 1.

While in the coverage area of the E-UTRA cell, the UE only on the UL carrier on the resource allocated by the cell (even if the carrier's resources are pre-configured, for example, in the Universal Integrated Circuit Card (UICC)) ProSe Direct Communication transmission will be performed.

For a UE with RRC_IDLE, the eNB may select one of the following options:

· The eNB may provide a mode 2 transmission resource pool in the SIB. A UE authorized for Prose direct communication uses these resources for ProSe direct communication in RRC_IDLE.

· The eNB may indicate in the SIB that it supports D2D but does not provide resources for ProSe direct communication. The UE needs to enter RRC_CONNECTED to perform ProSe direct communication transmission.

For UEs with RRC_CONNECTED.

· A UE of RRC_CONNECTED authorized to perform ProSe direct communication transmission indicates to the eNB that it wants to perform ProSe direct communication transmission when it is necessary to perform ProSe direct communication transmission.

· The eNB, using the UE context received from the MME, verifies whether the UE with RRC_CONNECTED is authorized for ProSe direct communication transmission.

· The eNB may configure the UE in RRC_CONNECTED by dedicated signaling with a mode 2 resource allocation transmission resource pool that can be used without restrictions while the UE is RRC_CONNECTED. Alternatively, the eNB may configure the UE in RRC_CONNECTED by dedicated signaling with a mode 2 resource allocation transmission resource pool that the UE is allowed to use only in exceptional cases, and may otherwise rely on mode 1.

This operation of the UE on resource allocation is illustrated in a simplified manner according to the state diagrams of FIGS. 7 and 8 . 7 shows a case in which the UE is in the RRC_IDLE state, and distinguishes between coverage and out-of-coverage. It should be noted that a UE that is out of coverage and is RRC-IDLE may use Mode 2 resource allocation. There are no exceptions currently defined for a UE that is RRC-IDLE. On the other hand, FIG. 8 shows a case in which the UE is in the RRC_CONNECTED state, and distinguishes between an in-coverage and an exceptional case. Obviously, in an exceptional case, a connected UE may use mode 2 resource allocation.

9 illustrates the use of transmit/receive resources for overlay (LTE) and underlay (D2D) systems.

Basically, the eNodeB controls whether the UE can apply mode 1 transmission or mode 2 transmission. If the UE knows the resource on which it will transmit (or receive) the D2D communication, in the current prior art, the UE uses only the corresponding resource for the corresponding transmission/reception. For example, in FIG. 9 , the D2D subframe will be used only to receive or transmit a D2D signal. Since the UE as a D2D device operates in a half duplex mode, the UE may receive or transmit a D2D signal at any time. Similarly, other subframes illustrated in FIG. 9 may be used for LTE (overlay) transmission and/or reception.

Transmission procedure for D2D communication

The D2D data transmission procedure is different according to the resource allocation mode. As described above for mode 1, the eNB explicitly schedules the scheduling assignment and resources for D2D data communication after a corresponding request from the UE. In particular, the UE may be notified by the eNB that D2D communication is generally allowed but no mode 2 resources (ie, resource pools) are provided; This may be done, for example, by exchanging a D2D communication interest indication by the UE and a corresponding response D2D communication response, as illustrated in FIG. 16 , where the above-mentioned corresponding exemplary ProseCommConfig information element specifies the commTxREsourcePool not included, which means that a UE wishing to initiate a direct communication involving transmissions must request the E-UTRAN to allocate a resource for each individual transmission. Thus, in this case, the UE has to request a resource for each individual transmission, and below, the different steps of the request/grant procedure for this Mode 1 resource allocation are listed as examples:

- Step 1: UE sends a Scheduling Request (SR) to the eNB through PUCCH;

- Step 2: eNB grants UL resource (for UE to transmit BSR) via PDCCH scrambled by C-RNTI;

- Step 3: UE transmits D2D BSR indicating buffer status through PUSCH;

- Step 4: eNB grants D2D resource (for UE to transmit data) via PDCCH scrambled by D2D-RNTI;

- Step 5: The D2D Tx UE transmits SA/D2D data according to the grant received in Step 4.

A scheduling assignment (SA) is a compact (low payload) message containing control information, eg, a pointer(s) to a time-frequency resource for the corresponding D2D data transmission. The content of the SA basically follows the approval received in step 4 above. The exact details of D2D approval and SA content have not yet been finalized, but the following agreements have been achieved as tentative assumptions about SA content.

Frequency resources are indicated by Rel-8 UL Type 0 resource allocation (5 -13 bits according to system BW).

· 1-bit frequency hopping indicator (according to Rel-8)

Note that some reinterpretation of indexing must be defined so that hopping does not use PRBs outside the resource pool configured for mode 2.

· Only a single cluster resource allocation is valid.

· This means that resource allocation will not straddle the gap if there is a gap in the resource pool in the frequency domain.

No RV indicator in SA

RV pattern for data: {0, 2, 3, 1}.

On the other hand, in the case of mode 2 resource allocation, steps 1 to 4 are not basically required, and the UE autonomously selects resources for SA and D2D data transmission from the transmission resource pool(s) configured and provided by the eNB. .

10 exemplarily illustrates a scheduling assignment and transmission of D2D data for two UEs, namely UE-A and UE-B, where a resource for transmitting the scheduling assignment is periodic, and a resource used for D2D data transmission is denoted by the corresponding scheduling assignment.

Resource pools for scheduling allocation and D2D data

When the UE is out of coverage, the resource pool for scheduling assignment (SA) and D2D data may be configured as follows:

- The resource pool used for reception of SA is pre-configured.

- The resource pool used for transmission of SA is pre-configured.

- The resource pool used for the reception of D2D data is pre-configured.

- The resource pool used for transmission of D2D data is pre-configured.

If the UE is within coverage, the resource pool for scheduling assignment (SA) may be configured as follows:

- The resource pool used for reception of SA is configured by the eNB through RRC in dedicated or broadcast signaling.

- The resource pool used for transmission of SA is configured by the eNB through RRC when mode 2 resource allocation is used.

- The SA resource pool used for transmission is not announced to the UE when mode 1 resource allocation is used.

- The eNB schedules specific resource(s) to be used for scheduling assignment transmission when mode 1 resource assignment is used. The specific resource allocated by the eNB is within the resource pool for the reception of the scheduling allocation provided to the UE.

UE coverage status for D2D

As already mentioned above (see, for example, FIGS. 7 and 8), the resource allocation method for D2D communication depends on the RRC state, that is, RRC_IDLE and RRC_CONNECTED, separately from the coverage state of the UE, that is, within the coverage, outside the coverage. do. A UE is considered to be in coverage if it has a serving cell (ie the UE is RRC_CONNECTED or camping on the cell in RRC_IDLE).

The two coverage states mentioned so far, i.e., in-coverage (IC) and out-of-coverage (OOC), are further distinguished as sub-states for D2D. 11 shows four different states in which a D2D UE may be associated, which may be summarized as follows:

- State 1: UE1 has uplink and downlink coverage. In this state, the network controls each D2D communication session. Further, the network configures whether UE1 should use resource allocation mode 1 or resource allocation mode 2 or not.

- State 2: UE2 has downlink coverage, but no uplink coverage, ie only DL coverage. The network broadcasts a (contention-based) resource pool. In this state, the transmitting UE selects resources used for SA and data from the resource pool configured by the network, and resource allocation in this state is only possible according to mode 2 for D2D communication.

- State 3: Since UE3 has no uplink and downlink coverage, UE3 is technically already considered out of coverage (OOC). However, UE3 is in the coverage of some UEs (eg UE1) that are UEs within the coverage of the cell (ie, such a UE may also be referred to as a CP-repeater UE), and thus the state 3 UE of FIG. The area may be indicated as a CP UE-repeater coverage area. This state 3 UE is also referred to as an OOC-state 3 UE. In this state, the UE receives some cell specific information (SIB) sent by the eNB and forwarded to the OOC-State 3 UE via PD2DSCH by the CP UE-repeater UE within the cell's coverage. The (contention-based) network-controlled resource pool is signaled by the PD2DSCH.

- State 4: UE4 is out of coverage and does not receive PD2DSCH from another UE in coverage of the cell. In this state, also referred to as state 4 OOC, the transmitting UE selects a resource used for data transmission from a preconfigured resource pool.

The reason for distinguishing state 3 OOC from state 4 OOC is primarily to avoid potentially strong interference between D2D transmissions from out-of-coverage devices and legacy E-UTRA transmissions. A typical D2D-capable UE will have resource pool(s) pre-configured for transmission of D2D SA and data to use while out of coverage. If this out-of-coverage UE transmits on this pre-configured resource pool near the cell boundary, the interference between the D2D transmission and the in-coverage legacy transmission may negatively affect the communication within the cell. If an in-coverage D2D-capable UE forwards the D2D resource pool configuration to an out-of-coverage device near the cell boundary, the out-of-coverage UE can limit its transmission to the resources specified by the eNodeB, thus legacy transmission in coverage interference can be minimized. Thus, RAN1 has introduced a mechanism whereby in-coverage UEs are forwarding resource pool information and other D2D related configurations to those devices (state 3 UEs) that are just outside the coverage area.

The Physical D2D Synchronization Channel (PD2DSCH) is used to carry this information about the in-coverage D2D resource pool to the UE in the network proximity so that the resource pool in the network proximity is aligned. The detailed content of PD2DSCH is not yet complete.

D2D discovery

Proximity based service (ProSe) direct discovery is a procedure used by a ProSe-enabled UE to discover other ProSe-enabled UE(s) in its vicinity, using an E-UTRA direct radio signal over a PC5 interface. is defined 12 schematically illustrates a PC5 interface for device-to-device direct discovery.

The upper layer handles the announcement of discovery information and authorization for monitoring. For this, the UE must exchange a predefined signal called a discovery signal. By periodically checking for discovery signals, the UE maintains a list of nearby UEs to establish a communication link if necessary. The discovery signal must be reliably detected even in a low signal-to-noise ratio (SNR) environment. In order to allow the discovery signal to be transmitted periodically, resources for the discovery signal must be allocated.

There are two types of ProSe direct discovery, open and restricted. Open is the case when there is no explicit grant required from the UE being discovered, while limited discovery only occurs with an explicit grant from the UE being discovered.

ProSe Direct Discovery may be a standalone service enabler in the discovery UE, which allows the discovery UE to use information from the discovered UE for a specific application. As an example, the information transmitted in ProSe direct discovery may be “find a taxi nearby”, “find a coffee shop”, “find the nearest police station”, and the like. Through ProSe direct discovery, the discovery UE may retrieve necessary information. Additionally, according to the obtained information, ProSe direct discovery may be used for subsequent operation of the telecommunication system, such as initiating ProSe direct communication.

ProSe Direct Discovery Model

ProSe direct discovery is based on several discovery models. An overview is given below. The model for ProSe direct discovery is defined in more detail in 3GPP TS 23.303 V12.1.0, Section 5.3, which is incorporated herein by reference.

Model A ("l am here")

Model A is also denoted as "I am here", in which the announcing UE broadcasts information about itself, such as its ProSe application identity or ProSe UE identity, in a discovery message, thereby allowing other entities in the available communication system Identify yourself to and communicate with him.

According to model A, two roles are defined for a ProSe-enabled UE participating in ProSe direct discovery. A ProSe-enabled UE may have the functions of an announcing UE and a monitoring UE. The announcing UE announces certain information that can be used by nearby UEs that have permission for discovery. The monitoring UE monitors the specific information of interest in close proximity to the announcing UE.

In this model A, the announcing UE broadcasts a discovery message at a predefined discovery interval, and the monitoring UE interested in this message reads the discovery message and processes it.

Model B ("who is there?"/ "are you there?")

This model defines two roles for ProSe-enabled UEs participating in ProSe direct discovery.

- Discoverer UE: The UE sends a request containing specific information about what it is interested in discovering.

- Discovered UE: The UE receiving the request message may respond with any information about the discoverer's request.

Model B is equivalent to "who is there/are you there", because the discovering UE transmits information about other UEs that it wishes to receive a response from. The transmitted information may be, for example, for the ProSe application identity corresponding to the group. Members of the group may respond to the transmitted information.

According to this model B, two roles are defined for a ProSe-enabled UE participating in ProSe direct discovery: a discoverer UE and a discoverer UE. The discoverer UE sends a request containing specific information about what it is interested in discovering. Meanwhile, the discoveree UE receiving the request message may respond with any information regarding the request of the discoverer UE.

The content of the discovery information is transparent to an access layer (AS) that is unaware of the content of the discovery information. Thus, at the access layer, no distinction is made between the various ProSe direct discovery models and types of ProSe direct discovery. The ProSe protocol ensures that only valid discovery information is delivered to the AS for announcement.

The UE may participate in the announcement and monitoring of discovery information in both RRC_IDLE and RRC_CONNECTED states for eNB configuration. The UE announces and monitors its discovery information according to the half-duplex constraint.

discovery type

13 illustrates a diagram illustrating IDLE and CONNECTED modes for a resource allocation procedure and upon reception of a discovery resource in D2D communication.

D2D communication may be network-controlled in which an operator manages switching between direct transmission (D2D) and a conventional cellular link, or the direct link may be managed by a device without operator control. D2D allows a combination of infrastructure-mode and ad hoc communication.

In general, device discovery is required periodically. Additional D2D devices utilize a discovery message signaling protocol for device discovery. For example, a D2D-capable UE may send its own discovery message, and another D2D-capable UE may receive this discovery message and use this information to establish a communication link. An advantage of a hybrid network is that if the D2D device is also within the communication range of the network infrastructure, a network entity, such as an eNB, may additionally assist in sending or configuring a discovery message. Coordination/control by the eNB in the transmission or configuration of the discovery message is also important to ensure that D2D messaging does not create interference to cellular traffic controlled by the eNB. Additionally, even if some of the devices are outside the range of network coverage, devices within coverage may assist the ad-hoc discovery protocol.

At least the following two types of discovery procedures are defined for the purpose of defining terms further used herein.

- Type 1: A resource allocation procedure in which a resource for announcing discovery information is allocated on a non-UE specific basis, which is further characterized by the following.

○ The eNB provides the UE(s) with a resource pool configuration used for announcing discovery information. The configuration may be signaled in the SIB.

○ UE autonomously selects radio resource(s) from the indicated resource pool and announces discovery information.

○ UE may announce discovery information on randomly selected discovery resources during each discovery period.

- Type 2: A resource allocation procedure in which resources for announcing discovery information are allocated on a UE-specific basis, which is further characterized by the following.

○ A UE with RRC_CONNECTED may request resource(s) for announcing discovery information from an eNB through RRC. The eNB allocates resource(s) through RRC.

○ Resources are allocated within the resource pool configured in the UE for monitoring.

Resources are allocated according to a type 2 procedure semi-permanently, for example, for discovery signal transmission.

If the UE is RRC_IDLE, the eNB may select one of the following options:

- The eNB may provide a type 1 resource pool for discovery information announcement in the SIB. A UE authorized for ProSe direct discovery uses these resources to announce discovery information in RRC_IDLE.

- The eNB may indicate in the SIB that it supports D2D but does not provide a resource for discovery information announcement. The UE needs to enter into an RRC connection to request a D2D resource for discovery information announcement.

For a UE in RRC_CONNECTED state, the UE authorized to perform ProSe direct discovery announcement indicates to the eNB that it wants to perform D2D discovery announcement. Then, the eNB, using the UE context received from the MME, verifies whether the UE is authorized for ProSe direct discovery announcement. The eNB may configure the UE to use a type 1 resource pool or a dedicated type 2 resource (or not use any resources) for discovery information announcement through dedicated RRC signaling. The resource allocated by the eNB is valid until a) the eNB deconfigures the resource(s) by RRC signaling, or (b) the UE enters IDLE.

A receiving UE with RRC_IDLE and RRC_CONNECTED monitors both type 1 and type 2 discovery resource pools as authorized. The eNB provides the resource pool configuration used for monitoring discovery information in the SIB. The SIB may also include a discovery resource for announcing in a neighboring cell.

wireless protocol architecture

14 schematically illustrates a radio protocol stack (AS) for ProSe direct discovery.

The AS layer interfaces with the upper layer (ProSe protocol). Accordingly, the MAC layer receives discovery information from an upper layer (ProSe protocol). In this situation, the IP layer is not used to transmit discovery information. In addition, the AS layer has a scheduling function, and thus the MAC layer determines the radio resource to be used for announcing the discovery information, received from the upper layer. In addition, the AS layer has a function of generating a discovery PDU, and thus the MAC layer constructs a MAC PDU carrying discovery information, and transmits the MAC PDU to the physical layer for transmission in the determined radio resource. No MAC header is added.

At the UE, the RRC protocol notifies the MAC of the discovery resource pool. The RRC also informs the MAC of the Type 2 resources allocated for transmission. There is no need for a MAC header. The MAC header for discovery does not include any field on which the filtering on layer 2 is based. Discovery message filtering at the MAC level is not considered to save processing or power compared to performing filtering at higher layers based on ProSe UE- and/or ProSe application ID. The MAC receiver forwards all reception discovery messages to the upper layer. The MAC will only forward correctly received messages to the upper layer.

In the following, L1 (PHY) is assumed to indicate to the MAC whether the discovery message was received correctly. Additionally, it is assumed that higher layers ensure that only valid discovery information is delivered to the access layer.

D2D Synchronization

The main task of synchronization is to allow the receiver to acquire time and frequency references. This criterion may be utilized for at least two purposes: 1) aligning the receiver window and frequency correction when detecting a D2D channel, and 2) aligning the transmitter timing and parameters when transmitting a D2D channel. Up to now, the following channels have been defined in 3GPP for synchronization.

- D2DSS D2D synchronization signal

- PD2DSCH physical D2D synchronization channel

- PD2DSS 1st D2D synchronization signal

- SD2DSS 2nd D2D synchronization signal

Also, the following terms for synchronization were negotiated in 3GPP and will be used illustratively in the remainder of this application.

- D2D synchronization source: a node that transmits at least a D2D synchronization signal. The D2D synchronization source may basically be an eNB or a D2D UE.

- D2D synchronization signal: a signal that enables the UE to obtain timing and frequency synchronization.

D2D synchronization can be viewed as a procedure similar to LTE cell search. To allow both NW control and efficient synchronization for partial/external coverage scenarios, the following receiver and transmitter synchronization procedures are currently under discussion within 3GPP:

Receiver Synchronization

The ProSe capable UE periodically discovers the D2DSS/PD2DSCH transmitted by the LTE cell and synchronization source (SS) UE (according to the LTE mobility procedure).

If any suitable cell is found, the UE camps on it and follows cell synchronization (according to LTE legacy procedures).

If any suitable D2DSS/PD2DSCH transmitted by the SS UE is found, the UE synchronizes its receiver to all incoming D2DSS/PD2DSCH (according to UE capabilities) and monitors it for incoming connections (scheduling assignments). It should be noted that the D2DSS transmitted by the D2D synchronization source being the eNodeB will be Rel-8 PSS/SSS (primary and secondary synchronization signals). A D2D synchronization source that is an eNodeB has a higher priority than a D2D synchronization source that is a UE.

Transmitter Synchronization

The ProSe capable UE periodically discovers the D2DSS/PD2DSCH transmitted by the LTE cell and the SS UE (according to the LTE mobility procedure).

If any suitable cell is found, the UE camps on it and follows cell synchronization for D2D signal transmission. In this case, the network may configure the UE to transmit D2DSS/PD2DSCH according to cell synchronization.

If no suitable cell is found, the UE verifies whether any of the incoming D2DSS/PD2DSCH can be further relayed (ie, the maximum hop count has not been reached), and then (a) further relay If a possible incoming D2DSS/PD2DSCH is found, the UE adapts its transmitter synchronization to it and transmits the D2DSS/PD2DSCH accordingly; or (b) if an incoming D2DSS/PD2DSCH that can be further relayed is not found, the UE operates as an independent synchronization source and transmits the D2DSS/PD2DSCH according to any internal synchronization criteria.

Additional details on the synchronization procedure for D2D can be found in clause 7 of TS 36.843 V12.0.1, incorporated herein by reference.

Cell selection and RRC connection setup

15 illustrates in a simplified and exemplary manner a prior art message exchange between a UE and an eNB for selecting a cell and establishing an RRC connection. The cell selection in step 2 is based, for example, on chapter 5.2.3 of eg v12.1.0 of 3GPP TS 36.304, incorporated herein by reference. A UE that is not camping on any Wide Area Network (WAN, eg, LTE) cell is considered out of coverage. Cell camping may be based on cell selection criteria/process defined in Chapter 5.2.3 of 3GPP TS 36.304-v 12.1.0. Thus, prior to completion of step 2, the UE is generally considered out of coverage (OOC). If the cell selection is successful and the UE camps on (either a suitable cell or an acceptable cell), the UE is in RRC Idle state. The UE continues in the RRC Idle state until step 7, that is, until it receives an RRCConnectionSetup message from the network, and then changes to the RRC Connected state.

One non-limiting exemplary embodiment provides an improved method for allocating radio resources to a transmitting terminal for performing direct communication transmission over a direct link connection, alleviating the problem discussed above. The independent claims provide one non-limiting, exemplary embodiment. Advantageous embodiments belong to the dependent claims.

According to the first aspect, an additional (temporary) transmission radio resource pool is defined by a network operator to perform direct communication transmission, and the additional radio resource pool for idle transmission has already been defined in the prior art. Although the idle transmission radio resource pool of the prior art is limited to the terminal in an idle state, the additional transmission radio resource pool according to the first aspect is independent of the idle or connected state of the terminal, while the temporary transmission radio resource pool is used by the transmitting terminal It is configured such that the amount of time available is limited. As a result, the base station broadcasts system information including information on the temporary transmission radio resource pool and corresponding configuration information in its own cell. As in the idle transmission of the radio resource pool of the prior art, the temporary transmission radio resource pool according to the first aspect is such a transmission that receives a system information broadcast for performing direct communication transmission to a receiving terminal through a direct link connection. Indicates radio resources usable by the terminal.

Different implementations of this first aspect are different in how the configuration information is achieved to limit the usage time of this additional resource pool, or when the terminal uses this resource of the temporary transmission radio resource pool once, the terminal uses the base station and additional requirements regarding having to establish (at least attempt to establish) a wireless connection.

By using this additional resource pool, it is possible for the terminal of the cell not to experience an interrupt while establishing a radio connection with the base station.

Accordingly, in one general aspect, the technology disclosed herein features a method for allocating radio resources to a transmitting terminal for performing direct communication transmission through a direct link connection with a receiving terminal in a communication system. The method includes a step performed by a transmitting terminal, wherein the step includes receiving a system information broadcast from a base station, wherein the system information broadcast includes direct communication transmission to the receiving terminal through a direct link connection. includes information on a temporary transmission radio resource pool indicating radio resources available by such a transmitting terminal that receives a system information broadcast to perform, and includes information on configuration information for the temporary transmission radio resource pool; The configuration information limits the amount of time that the temporary transmission radio resource pool can be used by the transmitting terminal. Corresponding terminals and base stations for participating in this method are provided.

According to the second aspect, the preconfigured transmission radio resource pool is made available to the terminals in the coverage of the cell of the base station. Such a preconfigured transmission radio resource pool is already known in the prior art for use in out-of-coverage situations, and the second aspect extends its use also to in-coverage situations of the terminal. "Preconfigured" in this context means, without receiving any system information from radio access, a preconfigured transmit radio resource, for example by information in the USIM card of the mobile phone or from higher layer signaling from the core network. It will be understood that the pool is announced to the terminal.

In a manner similar to the first aspect, a different implementation of the second aspect includes an option for limiting the amount of time a preconfigured transmit radio resource pool is available for a terminal when it is within the coverage of a cell, which would be done in a different way. can Another implementation of the second aspect requires that the terminal establish (at least attempt to establish) a radio connection with the base station when the terminal once uses this resource of the preconfigured transmission radio resource pool.

Accordingly, in one general aspect, the technology disclosed herein features a transmitting terminal for performing direct communication transmission via a direct link connection with a receiving terminal in a communication system. The transmitting terminal is preconfigured to have a preconfigured transmitting radio resource pool indicating radio resources available by the transmitting terminal for performing direct communication transmission to the receiving terminal through a direct link connection, wherein the preconfigured transmitting radio resource pool is usable when the transmitting terminal is within the coverage of the cell of the base station.

Additional advantages and advantages of the disclosed embodiments will be apparent from the specification and drawings. Advantages and/or advantages may be individually provided for by the disclosure of various embodiments and features and drawings of the specification, and need not all be provided in order to obtain one or more of the advantages and/or advantages.

These general and specific aspects may be implemented using systems, methods, and computer programs, and any combination of systems, methods, and computer programs.

According to the present invention, it is possible to provide an improved method for allocating radio resources to a transmitting terminal for performing direct communication transmission through a direct link connection, which alleviates the above-discussed problem.

Next, exemplary embodiments are described in more detail with reference to the accompanying diagrams and drawings.
1 shows an exemplary architecture of a 3GPP LTE system.
2 is an exemplary overview of the overall E-UTRAN architecture of 3GPP LTE.
3 shows an example subframe boundary on a downlink component carrier defined for 3GPP LTE (Release 8/9).
4 shows an exemplary downlink resource grid of downlink slots defined for 3GPP LTE (Release 8/9).
5 and 6 show 3GPP LTE-A (Release 10) Layer 2 with carrier aggregation activated for downlink and uplink, respectively.
7 and 8 provide an overview of the RRC_Idle, RRC_Connected, in-coverage and out-of-coverage resource allocation mode(s) of a cell and transitions between resource allocation modes available to the UE when out of coverage.
9 illustrates the use of transmit/receive resources for overlay (LTE) and underlay (D2D) systems.
10 illustrates a scheduling assignment and transmission of D2D data for two UEs.
11 illustrates coverage for four different states to which a D2D UE may be associated.
12 schematically illustrates a PC 5 interface for device-to-device direct discovery.
13 illustrates a diagram illustrating an idle and connected mode in reception of a discovery resource in D2D communication.
14 schematically illustrates a radio protocol stack for ProSe direct discovery.
15 illustrates an example prior art message exchange between a UE and an eNodeB for selecting a cell and establishing an RRC connection.
16 illustrates the exchange of a D2D communication interest indication message and a corresponding D2D communication response.
17 illustrates an example movement of a UE at the edge of a cell.
18 is a prior art view of selecting a cell, establishing an RRC connection, UE-A indicating interest in D2D communication, requesting dedicated radio resources for D2D communication transmission, and additionally indicating various different time periods; 15 is an extension of FIG. 15 illustratively illustrating a message exchange.
19 illustrates message exchange for a failed RRC connection establishment procedure.
20 illustrates such a period during which D2D communication transmission is not possible for the UE.
21 and 22 illustrate how a UE may apply a T-RPT pattern to a subframe for each mode 2 resource in mode 1.

Although the embodiment may be advantageously used in a mobile communication system such as a 3GPP LTE-A (Release 10/11/12) communication system as described in the technical background section above, the embodiment may be used to advantage in this particular exemplary communication network. It should be noted that the use is not limited.

A mobile station or mobile node or user terminal is a physical entity within a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that implements a predetermined set of functions and/or provides it to a node or other functional entity in a network. A node may have one or more interfaces that attach the node to a communication facility or medium through which the node may communicate. Similarly, a network entity may have a logical interface attaching the functional entity to a communication facility or medium through which it may communicate with other functional entities or corresponding nodes.

As used in the claims set and in this specification, "transmitting terminal" shall refer to a user terminal serving as a transmitter. "Receiving terminal" will conversely refer to a user terminal serving as a receiver. The adjectives "sending" and "receiving" are only intended to clarify a temporary action/role.

As used in the claim set and in this application, “direct communication transmission” will exemplarily refer to device-to-device (D2D) communication as discussed for the current LTE Release 12. The term “direct link connection” will exemplarily refer to a connection or communication channel through a PC5 interface that directly connects two D2D user terminals that allow the exchange of data directly without network intervention. That is, a communication channel is established between two user equipments of a communication system that are close enough to exchange data directly and thus bypass the eNodeB (base station).

The term "radio connection establishment procedure" as used in the claim set and this application may be understood to include or not include a random access procedure. Accordingly, initiating a radio connection establishment procedure may be understood as equivalent to transmitting a preamble of a random access procedure or equivalent to transmitting an RRC connection request message. Accordingly, in the context of 3GPP LTE, the radio connection establishment procedure may be a random access procedure followed by the RRC connection establishment procedure.

The term “dedicated radio resource” as used in the claim set and this application will be understood as a radio resource that is specifically allocated to a specific terminal by a base station (eNodeB). As such, as discussed in the background section, the dedicated radio resource may be a Mode 1 or Mode 2 resource. This term will be understood in contrast to a “common radio resource” that may be commonly used by the terminals of a cell; For example, a transmission radio resource pool defined by system information (eg, SIB18) is broadcast in a cell, and thus the same radio resource is available for use by a terminal receiving such system information.

An expression "initiating a radio connection establishment procedure" and similar expressions will be understood to mean that the terminal is required to attempt to establish a radio connection with a base station, but it should be borne in mind that the radio connection establishment procedure may fail. That is, the terminal is asked to attempt to establish a radio connection, but the terminal may succeed only in initiating the corresponding radio connection establishment procedure, and may not succeed in continuing the radio connection establishment procedure for successfully establishing the radio connection. can Thus, this representation is independent of the outcome, i.e. success (eg, receipt of an RRC connection setup message) or failure (eg, receipt of an RRC connection rejection message) of establishing a wireless connection, radio connection establishment procedure It will be understood to relate to this requirement of disclosing.

The expression (and similar expression) of "available transmission radio resource pool" as used in the claim set and this application means that when a terminal wants to perform direct communication transmission (eg, of scheduling assignment or direct communication data), It will be understood in a broad sense that a resource may not be selected from the transmission radio resource pool but may be selected and that it may be used rather than used by the terminal. Accordingly, the representation (and similar representations) of the transmission radio resource pool used is that the terminal actually intends to perform direct communication transmission, selects an appropriate resource from the transmission radio resource pool, and performs the direct communication transmission on the selected resource. It will be understood in a broad sense to perform.

The expression “in coverage” as used in the claim set and in this application should be broadly understood so that if the terminal successfully selects a cell, it is considered to be in coverage, independent of whether the terminal is idle or connected. The cell selection criteria are defined in TS 36.304. All in-coverage UEs may receive signaling from the network using broadcast messages (in Idle state and Connected state) or using dedicated (ie, one-to-one between UE and network) messages in the Connected state. For example, a UE is considered to be in coverage if it has a serving cell (ie, the UE is RRC_Connected or camping on the cell at RRC_Idle). Accordingly, the expression “out of coverage” should be conversely understood.

The term "preconfigured" as used in the claim set and in this application should be broadly understood as that the corresponding resource of the resource pool is known to the terminal without receiving any information from the radio access; That is, the preconfigured radio resource pool is available independently of cell and system information broadcast.

As used in the claim set and in this application, the term "radio resource" should be broadly understood to refer to a physical radio resource, such as a time-frequency resource.

As described in the background section, the UE may use different resources for D2D direct communication with other UEs according to its state and configuration by the eNB. The present inventors have identified numerous problems and disadvantages in the currently expected implementation of direct communication, that is, 3GPP D2D communication. The following different scenarios and problems are presented and will be described with respect to FIG. 18 . FIG. 18, which is an extension of FIG. 15, shows a UE indicating an interest in D2D communication and a request of the UE for a dedicated radio resource for D2D communication transmission, as well as various different times 0, 1, 2, A, B, C and D. additionally exemplified. Although not illustrated in FIG. 18 , as discussed in the background section, a UE may have pre-configured Mode 2 resources when out of coverage of a cell for SA and D2D data reception/transmission.

The eNB may determine that no mode 2 resource allocation is possible if the UE is RRC idle in its own network. For illustrative purposes, this type of network is denoted as a Type A network. In particular, in a type A network, the UE knows that D2D is allowed in SIB18, but since there is no common mode 2 resource (eg, resource pool according to mode 2) broadcast for it, it must first establish an RRC connection (see FIG. 15). Then, after properly configured for D2D (eg, using the D2D communication interest indication and the corresponding D2D communication response; see FIG. 16 ), the UE (according to how the UE is configured by the eNB, D2D communication In response to a response message), it may have access to a mode 2 resource for transmission. If the D2D communication response does not previously provide usable resources for D2D communication, for example, as a dedicated mode 2 resource pool, the UE previously in the background section (see steps 1-5 in the transmission procedure chapter for D2D communication) As discussed it may be necessary to explicitly request D2D related resources using dedicated signaling (scheduling request, buffer status report), which takes more time (see period C).

Moreover, as shown in FIG. 18 , period D is a delay in transmitting the first D2D after receiving the corresponding D2D grant. This may be considered negligible, but may not be negligible as calculations by the inventors indicate; Period D alone is approximately 300 depending on resource configuration such as periodicity of resource pool BITMAP for each SA and data, their offset (say from SFN0), exact time resource pattern of transmission (T-RPT) assigned, etc. It can be -400 ms.

The UE may perform D2D communication in complete period 2 illustrated in FIG. 18 or even during periods C and D if the D2D communication response from the eNB allows D2D but does not provide a mode 2 resource dedicated to the UE. None (in this case, the UE needs to specifically request the grant of a resource for a specific D2D transmission).

A Type A network allows the network operator full control over the usage of resources because the network operator will know how many UEs are performing D2D and thus can split the resources between D2D and LTE usage. However, the UE of this type A network cannot perform any D2D communication in an idle state. Additionally, even after entering the RRC connected state, the UE must transmit a D2D communication interest indication message, at least wait for an explicit network response to receive a D2D communication resource, and additionally when actual transmission of communication data may occur time (period C and/or period D) until This delay can easily add more than two seconds. In Release 12, D2D communication is mainly targeted for public safety use cases, so 2 second delay/interruption is not allowed, especially for VoIP/Voice/Conversation service class. This is particularly the case for cell-edge UEs that can tread in and out between out-of-coverage and in-coverage situations; See FIG. 17 for an example of a UE moving at the edge of a cell.

This problem is slightly alleviated in other types of networks where network deployment by the eNB provides common mode 2 D2D communication resources to be used in RRC idle state, and such networks may be denoted type B networks for illustrative purposes. In this type B network, the UE acquires SIB18 (including the corresponding mode 2 idle resource configuration, e.g., commIdleTxPool), and thus D2D using these mode 2 idle resources before in the type A network. will initiate communication; Thus, these UEs can conduct D2D data communication for a while before facing interrupts again in periods B, C and D. As a result, D2D communication is not possible in period 0, but the UE may perform D2D communication during period A.

Nevertheless, also in type B networks, the UE is prevented from performing D2D communication at a specific time, thus resulting in undesirable delays and/or interrupts. UE can continue to use mode 2 idle resources while in RRC idle state; Prior art mode 2 idle resources from SIB 18 can only be used in RRC idle. However, if the UE establishes an RRC connection (for some reason; for example because of the WAN, for example to access the Internet), and thus changes to the RRC connection state (see step 7 of FIG. 15 ), the UE: , as in step 7 of FIG. 15 , these resources of the mode 2 resource pool defined by SIB18 may no longer be used to continue or initiate D2D communication. In this case, in order to resume the previously started D2D communication or start a new D2D communication, the UE transmits at least a D2D communication interest indication message and waits for an explicit network response to receive the mode 2 D2D communication resource (or Even if you need to explicitly request approval of a resource for a specific D2D transmission, as discussed above with respect to steps 1 to 5 of the transmission procedure for D2D communication, you have to wait longer). This results in delays and/or interrupts in communication; The UE cannot perform D2D communication in periods B, C (and D).

FIG. 20 shows the different periods introduced with respect to FIG. 18 as blocks, and illustrates the difference between periods in which D2D communication transmission is not possible for the UE, for Type A and Type B networks.

19 is similar to FIG. 18, but illustrates a failed RRC connection establishment. As is evident from this, after initiating the RRC connection establishment, it fails (eg, because the RRC connection was rejected by the eNB, for other reasons such as cell reselection, or because T300 expiration is also possible). In either case, the UE remains in the RRC idle state. In a Type A network, this situation is particularly disadvantageous because the UE will not be able to perform D2D communication at all while in the idle state. On the other hand, for Type B networks, D2D communication is possible after SIB 18 acquisition with mode 2 idle resource configuration, i.e. during A and thereafter.

One neat solution for type B networks (which is also easy to implement) is that the mode 2 idle resource (commIdleTxPool) is in the RRC connection state, at least until the terminal is allocated by the eNodeB a dedicated resource available for direct communication transmission. It is also made available for use by the terminal (refer to period B + C (+ D) in FIG. 18 ).

The following first and second exemplary embodiments have been devised by the inventors to alleviate the described problem.

Next, some exemplary embodiments will be described in detail. Some of these, with certain key features described below with respect to various embodiments, are proposed to be implemented in the broad specification as given by the 3GPP standard and described in part in this background section. Although the embodiment may be advantageously used in a mobile communication system such as a 3GPP LTE-A (Release 10/11/12) communication system as described in the technical background section above, the embodiment may be used to advantage in this particular exemplary communication network. It should be noted that the use is not limited.

The description should not be understood as limiting the scope of the present disclosure, but merely as examples of embodiments for a better understanding of the present disclosure. Those skilled in the art should recognize that the generic principles of the disclosure described in the claims may be applied to different scenarios and in ways not expressly described herein. Correspondingly, the following scenarios, assumed for illustrative purposes of various embodiments, will not limit the invention as such.

first embodiment

A first set of embodiments will be described below. In order to simplify the description of the principles of the first embodiment, several assumptions are made, but these assumptions should not be construed as limiting the scope of the present application as broadly defined by the claims.

According to the first aspect, an additional transmission radio resource pool is defined by the network operator to perform direct communication transmission, and this additional resource pool is different from the idle transmission radio resource pool already known from the prior art in some ways. As described in the background section, if the network operator decides this, information on the transmission radio resource pool may be broadcast by the base station in that cell, so that terminals receiving the system information broadcast can When it is desired to perform direct communication with the user, the resource from the transmission radio resource pool may be autonomously used. The transmit radio resource pool from the prior art (referred to as idle transmit radio resource pool for ease of reference) is available by the terminal while the terminal is in the idle state, but is not available when changing the state of the terminal to connected This causes some of the previously mentioned problems.

On the other hand, the additional transmit radio resource pool introduced according to this first aspect (and referred to as a temporary transmit radio resource pool for ease of reference) will be used only temporarily (ie, for a limited amount of time), but whether the terminal is idle or whether it is connected or not. The network operator can control the amount of time this temporary transmission radio resource pool is available by a corresponding additional indication (configuration information) of the system information broadcast. Limiting the temporal availability of the temporary transmission radio resource pool can be implemented in several different ways, some of which will be described further below by way of example, but the time during which the temporary resource can be used is limited and , is consistent in that it can be controlled by the base station (ie the network operator).

A network operator may be hesitant to make the idle transmission radio resource pool commonly available to terminals through system information broadcast, but rather allocate a specific dedicated resource pool to a specific terminal or even assign only a specific dedicated physical resource to each terminal. You may prefer to allocate only resources, so you can maintain full control (or at least as much control as possible) over your own radio resources. As a result, the network operator may, for example, be able to use resources from this idle transmission radio resource pool almost infinitely (as long as the terminal remains idle), or because the network may Because there is no information and it is not known how many UEs are actually using these idle mode D2D resources (idle mode UEs are not known at the cell level, but only at the tracking area level, which is much larger than the cell level), the UEs in their cells are autonomous would not want to use the idle transmit radio resource pool of the prior art; This does not allow the network to conclude whether the idle mode D2D resources are too few (meaning many collisions in D2D resource usage) or too many (meaning unnecessary consumption of other LTE resources). On the other hand, the additional temporary transmit radio resource pool allows the network operator to precisely define the physical resources available for a configurable amount of time (more or less). This, of course, has the immediate advantage that as soon as the terminal receives and processes the corresponding system information broadcast with information about the temporary transmission radio resource pool, the terminal can obtain access to the resource for direct communication transmission, while the network The operator can flexibly control the time when these resources are commonly available to terminals in the cell. Since the amount/number of UEs establishing an RRC connection will be significantly limited by the total number of UEs in idle mode within the cell, an additional temporary transmit radio resource pool is added to the prior art (mode 2) idle transmit radio resource pool broadcast in SIB18. It can be much more efficient/smaller in size compared to In addition, the additional temporary transmission radio resource pool is particularly advantageous for a terminal in a cell that will not actually provide such an idle transmission radio resource pool. However, it is also advantageous for terminals of other types of cells that actually broadcast the idle transmission radio resource pool, which in this case is that the terminal is already in a connected state but has not yet been allocated a dedicated resource to be used for direct communication transmission by the base station. This is because resources for direct communication transmission are also available in the case or when actual transmission of D2D communication data has not yet been performed.

Overall, by providing a temporary transmit radio resource pool of the first aspect in the system information broadcast of a cell instead of or in addition to the idle transmit radio resource pool of the prior art, delay or interruption of direct communication to the terminal is reduced or or virtually eliminated, while at the same time giving the network operator as much control as possible over these resources. According to a specific implementation, in a cell of the Type A network (ie, not including the idle transmission radio resource pool of system information), the terminal selects the temporary transmission radio resource pool discussed above, that is, period A as shown in FIG. 18 . , after receiving during period B, period C, and period D, resources from it can be used. In the cell of the type B network, the terminal may use a resource from the temporary transmission radio resource pool during period B + C + D.

A further implementation of the first aspect relates to how the configuration information may limit the amount of time a temporary transmission radio resource pool is available by a transmitting terminal in a cell. For example, the system information broadcast may directly indicate an appropriate amount of time for a temporary transmission radio resource pool, eg, 10 ms, 100 ms, 2000 ms. Then, depending on the particular implementation, this indicated amount of time will be interpreted by the terminal in that, for example, after reception of the system information broadcast, the temporary transmission radio resource pool is available for this particular time. Alternatively, instead of starting a timer when the terminal receives the system information broadcast, the transmitting terminal uses the temporary transmission radio resource pool (eg, by sending a scheduling assignment to another terminal in direct communication transmission) A timer may be started at startup. In either case, this has the particular advantage that this configuration is independent of the radio connection establishment procedure and its consequences, and thus is predictable by the base station.

Alternatively or additionally, in order to directly indicate the amount of time, by specifying a specific condition/event that causes the terminal to no longer use the resource, the time during which the temporary transmission radio resource pool is available can be “indirectly” limited. . For example, the system information broadcast may include a command related to a temporary transmission radio resource pool, so that a terminal wishing to use such a resource can also avoid having the terminal remain idle indefinitely using such a resource. It should attempt to establish a wireless connection with the base station for Then, the terminal, for example, only establishes a connection and the base station allocates a dedicated radio resource to the terminal (then it will instead be used for possible direct communication transmission (period A+B+C in Fig. 18) )), or if the connection cannot be established or denied, the terminal is allowed to use the resources from the temporary transmission radio resource pool until it is notified of such establishment failure (see period A in FIG. 19), or Even if the connection with the terminal is established, the base station at this time may not allow the terminal to perform direct communication transmission (refer to period A+B in FIG. 18 ). In addition, in view of the long time that the terminal may take to actually use the dedicated radio resource allocated to the terminal by the base station, an additional alternative is, the time during which the temporary transmission radio resource pool is available, the terminal After establishing a connection and receiving a dedicated radio resource for direct communication transmission from the base station), it can be extended to the point in time when direct communication transmission of SA or data is actually performed using these dedicated radio resources allocated to the terminal by the base station. (See period A + B + C + D in Figure 18).

The actual command to establish a connection is, for example, a certain amount of time that the terminal needs to (at least) start establishing a connection (eg, immediately after receiving a system information broadcast, or to use a temporary transmission radio resource pool). after starting) can be displayed. Another option is to be required to initiate connection establishment before the terminal is allowed to use radio resources from the temporary transmission radio resource pool for direct communication transmission. For this purpose, it may be exemplarily understood that the terminal initiates connection establishment with the base station by transmitting the preamble of the random access procedure.

In addition, in the case of the first aspect, as in the case of the idle transmission radio resource pool of the prior art, the temporary transmission radio resource pool includes resources available for direct communication transmission of the scheduling assignment and direct data to other terminals through the direct link. It is possible to distinguish between the resources available for direct communication transmission of Accordingly, the cell may provide different resources to be used for transmitting the scheduling assignment and data.

Several different implementations of the first aspect have been described above. Hereinafter, the principles of the first aspect and its implementation are applied to an LTE system in an exemplary manner (as described in the background section).

In particular, the current 3GPP standardization expects the use of SIB18, which contains some information related to direct communication and discovery of ProSe. As a result, information about the above-described temporary transmission radio resource pool and its configuration information can be a part of this SIBType 18. Of course, it should be noted that for the purposes of this first aspect, any other type of system information block may be used to carry such information. Also, in the specific selected example, the field and configuration information of the system information block carrying the temporary transmission radio resource pool are referred to as “commTxPoolTemp”. It should also be noted that, for the purposes of this aspect, any other name for the field may be chosen, or information for the temporary transmit radio resource pool may be inserted into a field different from the corresponding configuration information. The same applies to the name and format selected for the specific variables commSA-TxResourcePoolCommonTemp, commData-TxResourcePoolCommonTemp.

Accordingly, the following definition of an information element of system information block type 18 is taken only as an example.

SystemInformationBlockType18 information element

Significant changes introduced in this exemplary system information block type 18 information element relative to the first aspect over the prior art are bolded and underlined for ease of identification. As is evident therefrom, in this particular example, the configuration information is embodied in the variable “allowedTime” and has exemplary time values of 100 ms, 200 ms, etc. as indicated above, thus directly limiting the amount of time. Of course, the specific time value and also the number of configurable time values are to be understood as examples only, and any other time value and number of configurable time values may be appropriately selected. By reading the value indicated by the "allowedTime" variable, the terminal determines that the temporary transmission radio resource pool is determined after reception of the system information broadcast (or after the terminal starts using resources from the temporary transmission radio resource pool to perform direct communication). It can determine how long it can be used, or a corresponding timer can be set up, started, and monitored by the UE.

Alternatively, another example of the definition of SIB18 is given below. As in the exemplary definitions above, any name given to a variable and also a specific value given to a variable may be seen as examples only.

SystemInformationBlockType18 information element

Significant changes introduced in this exemplary system information block type 18 information element relative to the first aspect over the prior art are bolded and underlined for ease of identification. As is apparent from the above, the configuration variable timeToInitiateRRCConnEst is included to indirectly limit the use of the temporary transmit radio resource pool (ie, commTxPoolTemp) based on different exit conditions as will be explained. By use of this configuration variable timeToInitiateRRCConnEst, the UE is instructed to attempt to establish an RRC connection with the eNB within an exemplary time, such as 1 or 5 ms, as indicated above. Then, according to different UE behavior, for example, the UE waits until the RRC connection is established and the eNB allocates a dedicated radio resource to the terminal, or until the UE recognizes that the RRC connection establishment has failed, or the UE Temporary transmission until the UE is notified by the eNB that it is not allowed to perform direct communication in the cell, or until actually performing direct communication of SA or data using the dedicated resources allocated to the UE by the eNB It may be allowed to use the resources of the radio resource pool.

It should also be noted that this new field commTxPoolTemp is randomly generated in SIB18 and thus gives the network operator control to decide whether or not to broadcast it in the cell. Consequently, since the field commIdleTxPool (already defined in the prior art) is also arbitrary, the network operator can configure (via the eNB) one or both of the fields commIdleTxPool and commTxPoolTemp or none of them when needed. there is.

Of course, combinations of the SIB 18 definitions shown above are possible, allowing configurations where the commTxPoolTemp field contains the variables "allowedTime" and "timeToInitiateRRCConnEst".

second embodiment

The second aspect of the present invention solves the above-mentioned fundamental problem(s) of the prior art in a different way. Instead of defining an additional transmission radio resource pool in the system information broadcast as was done for the first aspect, this second aspect applies not only when the terminal is out of coverage of the cell (as defined in the present prior art) but also It is based on the idea of using a pre-configured transmission radio resource pool for possible direct communication transmission when the terminal is within the coverage of the cell. What is preconfigured in this situation will be distinguished from those "configured" resources that are configured by system information broadcast from the base station. That is, the pre-configured resource is announced to the terminal (and the base station) independently of the cell and the system information broadcast from the cell, ie, without receiving any information from, for example, radio access. Thus, the pre-configured radio resource is a prior art already used by a UE that is outside the cell's coverage, ie has not received any system information broadcast from the base station of any cell.

For example, a preconfigured pool of transmit radio resources can be defined by the network operator and hardcoded into a common sim/USIM card, which is insertable and usable by most common mobile phones. Alternatively, higher layer signaling may be used to provide the terminal with appropriate information about this pre-configured transmission radio resource pool from the core network via, for example, an Internet protocol or a connectionless-layer protocol.

In addition, by using radio resources from the pre-configured transmission radio resource pool even when within the coverage of the cell, the terminal receives the system information broadcast, whether the system information broadcast includes information on the resource pool, radio Direct communication transmission may be performed independently of whether a connection is established or in which state (idle or connected) the terminal is. Accordingly, the terminal is not interrupted, delayed, or interrupted with respect to direct communication transmission. Thus, in contrast to the first embodiment, according to the second aspect, the terminal may also perform direct communication transmission in period 0 in addition to periods A, B, C and D.

One option is to reconfigure the preconfigured transmission radio resource pool already defined in the prior art for the terminals out of coverage, in order to apply also for the terminals within the coverage of the cell of the base station.

Meanwhile, an alternative option would be to configure a pre-configured transmission radio resource pool within the new coverage in addition to such a pre-configured transmission radio resource pool already defined in the prior art for the out-of-coverage terminal, and the pre-configured transmission radio resource within the coverage The pool applies to terminals that are within coverage, but is not available to those terminals that are still outside the coverage of the cell of the base station. In this case, both the preconfigured transmit radio resource pool in coverage according to the second aspect as well as the preconfigured transmit radio resource pool outside the coverage of the prior art may be stored on the sim/USIM card or alternatively, as mentioned above As described above, it may be defined by higher layer signaling.

In a further development of the second aspect, the network operator will have some control over whether this pre-configured pool of transmit radio resources is actually available in its cell (even if it is pre-configured for a particular terminal). For example, the network operator may determine that such a resource of a pre-configured transmission radio resource pool in its cell will not be available to the terminal. For this purpose, the system information broadcast will appropriately indicate whether terminals within the cell's coverage are permitted to use it.

One simple possibility for such an indication is a 1-bit flag in the system information, one bit value indicating permission, the other bit value indicating that the use of a preconfigured transmit radio resource pool for a terminal in coverage of the cell is not. Indicates that this is not allowed.

Alternatively, the system information may optionally include configuration information for the preconfigured transmit radio resource pool, so that in the absence of the configuration information, the terminal understands that the preconfigured transmit radio resource pool will not be used. On the other hand, when the configuration information for the preconfigured transmission radio resource pool exists in the system information, and thus is received by the terminal attached to the cell, the terminal can continue to use the preset transmission radio resource pool for direct communication transmission understands, but also applies the above configuration information to its use.

Configuration information may change. For example, according to an improvement to the second aspect, it is also advantageous to restrict in time the use of the preconfigured transmission radio resource pool while within the coverage of the cell. As discussed in the first aspect, several possibilities exist for how a particular radio resource pool limits the amount of time available for a terminal. Accordingly, the configuration information for the pre-configured transmit radio resource pool may be similar or identical to that discussed above for the temporary transmit radio resource pool.

Specifically, for example, the system information broadcast may directly indicate an appropriate amount of time for a preconfigured transmission radio resource pool, eg, 10 ms, 100 ms, 2000 ms. Then, depending on the particular implementation, this indicated amount of time will be interpreted by the terminal in that, for example, after reception of the system information broadcast, the pre-configured transmission radio resource pool is available for this particular time. Alternatively, instead of starting the timer when the terminal receives the system information broadcast, the transmitting terminal uses a preconfigured transmission radio resource pool (eg, by sending a scheduling assignment to another terminal in direct communication transmission) A timer may be started when the

Alternatively or additionally, in order to directly indicate the amount of time, by specifying a specific condition/event that prevents the terminal from using the resource any longer, the time during which the pre-configured transmission radio resource pool is usable can be “indirectly” limited. there is. For example, the system information broadcast may include a command related to a preconfigured pool of transmit radio resources, so that a terminal wishing to use such a resource also avoids that the terminal is kept idle indefinitely using such a resource. In order to do this, it must attempt to establish a wireless connection with the base station. Then, the terminal, for example, only establishes a connection and the base station allocates a dedicated radio resource to the terminal (then it will instead be used for possible direct communication transmission (period 0+A+B in Fig. 18) +C)), or if the connection cannot be established or denied, the UE uses the resource from the preconfigured transmission radio resource pool until notified of such establishment failure (see period 0+A in FIG. 19) Even if allowed to do so, or establish a connection with the terminal, the base station at this time may not allow the terminal to perform direct communication transmission (refer to period 0+A+B in FIG. 18 ). In addition, in view of the long time that it may take for the terminal to actually use the dedicated radio resource allocated to the terminal by the base station, an additional alternative is, the time during which the pre-configured transmission radio resource pool is available, After establishing a radio connection and receiving a dedicated radio resource for direct communication transmission from the base station), it can be extended to the point in time when direct communication transmission of SA or data is actually performed using these dedicated radio resources allocated to the terminal by the base station. There is (see period 0+A + B + C + D in Figure 18).

The actual command to establish a connection is, for example, a specific amount of time that the terminal needs to (at least) start connection establishment (eg, immediately after receiving a system information broadcast, or using a preconfigured transmission radio resource pool). after starting to do) can be displayed. Another option is to be required to initiate connection establishment before the terminal is allowed to use a radio resource from a preconfigured transmission radio resource pool for direct communication transmission. For this purpose, it may be exemplarily understood that the terminal initiates connection establishment with the base station by transmitting the preamble of the random access procedure.

The preconfigured transmit radio resource pool may define the actual physical radio resources (ie, time and frequency), and may optionally also define a specific transmit format or power associated with the physical radio resource. In addition, when the terminal is within coverage and uses a preconfigured transmission radio resource pool for direct communication transmission, the power for such transmission may be controlled by the base station (in a conventional manner).

Several different implementations of the second aspect have been described above. Hereinafter, the principles and implementations of the second aspect are applied to an LTE system in an exemplary manner (as described in the background section). According to some implementations discussed above for the second aspect, the broadcast by the base station is The system information is adapted to permit/prohibit and/or configure the use of a preconfigured transmission radio resource pool when within coverage.

As mentioned for the first aspect, the current 3GPP standardization anticipates the use of SIB18, which contains some information related to ProSe direct communication and discovery, and may carry the aforementioned flag or configuration information. Of course, it should be noted that for the purposes of this second aspect, any other type of system information block may be used to carry such information. In the following, a very specific example is provided in which configuration and configuration variables are given specific names (i.e., usePreconfigResInCoverage, allowedTime, timeToInitiateRRCConnEst) and the variables are specifically set up (i.e., ms100, ms200, ms300, etc., ms01, ms05, etc.). It should also be noted that, for purposes of this second aspect, any other name may be chosen for the field, and the actual value for the variable may be different.

SystemInformationBlockType18 information element

Significant changes introduced in this exemplary system information block type 18 information element to the second aspect relative to the prior art are bolded and underlined for ease of identification.

As is evident from the above, the configuration information field "usePreconfigResInCoverage" is optional, so that if this field is present in the system information broadcast, the corresponding preconfigured transmit radio resource pool (mode 2 resource) is available when the UE is within coverage. Conversely, in the absence of this field, the UE derives that the corresponding preconfigured transmission radio resource pool is not available in the cell.

The configuration variables "allowedTime" and "timeToInitiateRRCConnEst" are as already known from the first aspect discussed above, and are defined for this second aspect in the same way. As is evident from the example above, these can be defined even simultaneously, if so determined by the eNB, thus allowing a pre-configured pool of transmit radio resources within coverage to directly and/or indirectly limit the amount of time available. Thus, in this particular example, a portion of the configuration information is implemented as the variable “allowedTime” and has exemplary time values of 100 ms, 200 ms, etc. as indicated above, thus directly limiting the amount of time. By reading the value indicated by the "allowedTime" variable, the terminal receives the system information broadcast (or after the terminal starts to use the resource from the temporary transmission radio resource pool to perform direct communication) the preconfigured transmission radio resource It can determine how long the pool can be used, or a corresponding timer can be set up, started, and monitored by the UE.

Likewise, the configuration variable timeToInitiateRRCConnEst may be included to indirectly limit the use of the temporary transmit radio resource pool (ie, commTxPoolTemp) based on different exit conditions as will be described. By use of this configuration variable time ToInitiateRRCConnEst, the UE is instructed to attempt to establish an RRC connection with the eNB within an exemplary time, such as 1 or 5 ms, as indicated above. Then, according to different UE behavior, for example, the UE waits until the RRC connection is established and the eNB allocates a dedicated radio resource to the terminal, or until the UE recognizes that the RRC connection establishment has failed, or the UE Until the UE is notified by the eNB that it is not allowed to perform direct communication in the cell, or until actually performing direct communication of SA or data using the dedicated resources allocated to the UE by the eNB, the preconfigured It may be allowed to use the resources of the transmit radio resource pool.

Also, although this second embodiment has been described as a standalone solution as opposed to the first embodiment, it should be noted that still generally this second embodiment can be combined with the first embodiment.

third embodiment

With respect to D2D communication and current developments, the inventors have identified additional problems. More specifically, apart from the above problem regarding different periods of time during which the UE is prohibited from performing D2D communication in different scenarios, another problem relates to state 3 and state 4 OOC UEs. In particular, it is not yet clear how a particular UE knows whether it is in state 3 (CP UE-repeater) or state 4. This causes an additional problem that it is not clear to the UE which resource and transmission power the UE should use to perform D2D communication.

11 and the corresponding description in the Background section describe four general states in which a UE may be, which is summarized as follows.

State 1: In cell coverage very close to the cell center (IC)

State 2: In-Cell Coverage at Cell Edge (IC)

State 3: Out of cell coverage just outside the cell; Such UEs may create some WAN interference “if” transmitting on conflicting resources with high transmit power.

State 4: Out of "real" cell coverage - cannot create any kind of WAN interference, even when transmitting on conflicting resources with high transmit power.

As is clear, in both state 3 and state 4, the UE is out of cell coverage, but it is unclear how the UE can distinguish between state 3 and state 4, which means that the UE is only out of cell coverage; That is, it only knows that no WAN cell has been camped on.

The following solution(s) are possible.

When a UE receives a PD2DSCH, it considers itself to be in state 3, otherwise, if the UE has not received a PD2DSCH for a certain predefined (or configurable) time, it considers itself to be in state 4. As described in the background section, the PD2DSCH is physical layer information transmitted by the eNB to the Out-of-Coverage (OOC) UE via some IC UE (IC UE forwards the PD2DSCH). PD2DSCH signals some resources for D2D communication. When received by the OOC UE, the resource received in the PD2DSCH for D2D communication has priority over any pre-configured Mode 2 resource available to the OOC UE. This is advantageous because the use of otherwise preconfigured Mode 2 resources may create some WAN interference, which would otherwise be considered such a UE in state 4 and be unable to transmit on conflicting resources with high transmit power. because there is

When a state 3 UE stops receiving PD2DSCH or D2DSS (D2D synchronization signal) for a predefined period, it will consider itself as a state 4 UE again.

By specifying how the UE distinguishes between state 3 and state 4, the resource and transmit power that the UE must use to perform D2D communication is selectable/calculable in an efficient manner so as not to cause any problem (interference) in WAN communication. Do.

It should be noted that the third embodiment described above may be combined with the first and/or second embodiment described above.

4th embodiment

Another problem identified for D2D communication is that it is unclear from current standardization which UEs are proposed to forward PD2DSCH to OOC UEs.

The following alternative solutions are possible. Combinations of the following are also possible.

In general, a UE that is very well within cell coverage (eg, good RSRP and RSRQ measurements of the serving cell) but not close to the cell center may be a good option for forwarding PD2DSCH. Specifically, a UE that is between a predefined threshold of wireless reception, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ) (for example, in this case RSRP/RSRQ measurement is a specific threshold “x” and a threshold between "y"). In this case, threshold x and threshold y are broadcast together with the content of the PD2DSCH.

Another possible candidate for forwarding PD2DSCH is a UE transmitting/forwarding D2DSS. The content of the PD2DSCH is broadcast.

Another possible solution is to explicitly request in dedicated signaling that the network forward the PD2DSCH to a specific UE. The content of the PD2DSCH is signaled or broadcast to the UE by dedicated signaling.

One possible combination of the above solutions is a UE that has already forwarded D2DSS but is within good enough cell coverage, ie, RSRP or RSRQ is between the corresponding thresholds.

It should be noted that the fourth embodiment may be used with any one or any combination of the first, second and third embodiments.

5th embodiment

Another problem identified for D2D communication relates to receive/transmit operation for D2D communication. As mentioned in the technical background section, depending on the resource allocation mode, the D2D communication transmission operation looks slightly different. For mode 1 D2D communication, the eNB issues a D2D grant scrambled with D2D-RNTI, that is, (E-PDCCH) to the D2D transmitting UE, and the D2D transmitting UE sends SA transmission and also resources for data (ProSe/D2D data). ) is assigned. More specifically, the D2D grant is at least an index for an SA resource (SA resource index) indicating a time/frequency resource to be used by a D2D transmitting UE for transmission of an SA within the SA resource pool, and a T-RPT index and data RB It includes an allocation field, which basically indicates a time/frequency resource for D2D data transmission. The T-RPT index field refers to one entry in a table listing all available T-RPT patterns, for example, the table contains 128 entries. The time resource pattern of transmission (T-RPT pattern) defines the time resource pattern of D2D data transmission in the D2D data resource pool.

When receiving the D2D grant from the eNB, the D2D transmitting UE uses the SA resource index to determine a subframe and frequency resource in the SA resource pool to be used for transmission, which is a retransmission of the SA message, respectively. Additionally, the D2D transmitting UE determines the subframe (and potentially also the frequency resource based on some other information conveyed in the D2D grant) to be used for transmission of the D2D data PDU, at least the T-RPT received within the D2D grant. Use index information. The function of how to derive a subframe for transmission of a D2D data PDU is different for mode 1 and mode 2 D2D transmission. For mode 2 D2D transmission, the D2D transmitting UE will apply the T-RPT pattern to the subframe marked as 1 in the resource full bitmap. In essence, the D2D transmitting UE applies the T-RPT pattern to those subframes defined as potential D2D subframes for mode 2 transmission according to the D2D mode 2 data transmission resource pool. An example is shown in FIG. 22 .

1 in the transmission resource full bitmap indicates a so-called D2D subframe, that is, a subframe reserved for D2D mode 2 transmission. The T-RPT pattern is applied to such D2D subframes. As can be seen in FIG. 22 , such a D2D subframe in which the corresponding T-RPT entry is 1 is for D2D data PDU transmission (a subframe in which both the resource pool bitmap entry and the T-RPT bitmap entry are 1). will be used As already mentioned in the technical background, in the case of mode 2 resource allocation, the D2D transmitting UE autonomously selects the T-RPT pattern, and signals it in the SA, so that the D2D receiving UE (after correctly decoding the SA) receives the received A time/frequency resource of D2D data transmission may be determined based on the T-RPT pattern. There is no D2D grant for Mode 2 D2D transmission.

For D2D transmission in mode 1, the eNB allocates a T-RPT pattern to be used for D2D transmission, and signals it to the D2D transmitting UE through D2D grant as already described above.

Considering the absence of D2D transmission resource pool for mode 1, since all uplink subframes can be D2D subframes, the parameters of T-RPT are directly applied to physical uplink subframes. According to one exemplary embodiment, the D2D transmitting UE transmits the T-RPT pattern indicated by the T-RPT pattern index of the D2D grant to all subframes of the resource full bitmap, that is, not only the subframes in which the bitmap entry is 1 However, it will be applied to subframes that are 0. An example of mode 1 D2D data transmission is shown in FIG. 21 .

As can be seen, the same T-RPT pattern used in the example scenario illustrating mode 2 D2D transmission is also taken here, but for mode 1, this applies to all (UL) subframes of the resource pool. do. Since there is no data transmission resource pool defined/configured for mode 1, the D2D transmitting UE may apply the T-RPT pattern to the mode 2 data transmission pool or alternatively to the data reception resource pool. Importantly, some reference to each starting subframe where the T-RPT pattern is applied to mode 1 is needed. Alternatively, there may be some timing relationship between the first transmission of D2D data and a predefined SA. For example, the first D2D mode 1 data transmission opportunity (ie, this is the starting subframe of the T-RPT pattern) occurs x ms after the last transmission of the SA message.

The T-RPT pattern is used differently depending on whether mode 1 or mode 2 D2D data transmission is used by the D2D transmitting UE. Therefore, the D2D receiving UE should be able to distinguish between mode 1 and mode 2 D2D transmission. More specifically, when receiving an SA in the SA resource pool, the D2D receiving UE may correctly interpret the T-RPT pattern, that is, to determine the correct time/frequency resource of the corresponding D2D data transmission, It is necessary to recognize whether the SA was transmitted by mode 1 D2D transmission or by mode 2 D2D transmission. According to another exemplary embodiment, the SA message includes an explicit indicator of the resource allocation mode used for D2D communication, that is, a new field of the SA message indicates whether mode 1 is used or mode 2 is used for D2D data transmission. Indicate whether or not it has been used.

As an alternative solution, the transmission/resource allocation mode is implicitly indicated by the signaled T-RPT pattern in the SA message. The available T-RPT patterns pre-configured or given in the table are divided into two sets, one set of T-RPT patterns used for mode 1 transmission and a second set of T-RPT patterns used for mode 2. For example, assuming 128 different T-RPT patterns, patterns 0-63 can be used for mode 1 D2D transmission, while T-RPT patterns with indices 64-127 are reserved for mode 2. Based on the received T-RPT index in the SA, the D2D receiving UE may understand whether the transmitting UE is using resource allocation mode 1 or mode 2, respectively.

As a further alternative solution according to another exemplary embodiment, the transmission/resource allocation may be derived from the value of the TA field included in the SA. Because mode 1 transmission and mode 2 transmission use different transmission timings, the receiving UE can distinguish between mode 1 transmission and mode 2 transmission based on the value of the theta field. For example, the TA value for mode 2 transmission is always 0, while for mode 1, the TA value is set to the UE's NTA value, that is, the UE uses legacy uplink transmission timing for mode 1 D2D transmission. .

As a further alternative, the resource allocation/transmission mode may be implicitly indicated by the frequency resource used for transmission of the SA message. For example, the SA message sent by the mode 2 transmitting UE is different from the frequency resource used for the SA transmission of the mode 1 transmitting UE. More specifically, the SA transmission resource pool for mode 2 is different from the resources allocated by the eNB for SA transmission (mode 1).

Another alternative solution according to a further exemplary embodiment of the present invention is to define the T-RPT pattern bitmap length in such a way that there is no ambiguity between mode 1 transmission and mode 2 transmission. More specifically, the T-RPT pattern bitmap length must be equal to the resource pool bitmap length to which the T-RPT pattern is applied. Taking the example shown in Figures 21 and 22 discussed above, the T-RPT pattern length should be 30 bits.

Since the T-RPT pattern for both mode 1 and mode 2 is applied to the same starting subframe, for example, the starting subframe of the resource pool, the D2D receiving UE needs to distinguish between mode 2 transmission and mode 1 transmission there is no

It should be noted that the fifth embodiment may be used with any one or any combination of the first, second, third and fourth embodiments.

Hardware and software implementations of the present disclosure

Other illustrative embodiments relate to implementations of the various embodiments described above using hardware and software. In this regard, user equipment (mobile terminal) and eNodeB (base station) are provided. User equipment and base station are adapted to perform the method described herein.

Additionally, it is recognized that various embodiments may be implemented or performed using a computing device (processor). The computing device or processor may be, for example, a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device, or the like. Various embodiments may also be performed or implemented by combinations of such devices.

Additionally, various embodiments may also be implemented using software modules executed directly by a processor or in hardware. Combinations of software modules and hardware implementations may also be possible. A software module may be stored on any kind of computer-readable storage medium, such as, for example, RAM, EPROM, EEPROM, flash memory, registers, hard disk, CD-ROM, DVD, and the like.

It should be further noted that individual features of different embodiments may be subject to subject matter for other embodiments, either individually or in any combination.

It will be appreciated by those skilled in the art that many changes and/or modifications may be made to the present disclosure as shown in the specific embodiments. Accordingly, this embodiment is to be considered in all respects as illustrative and not restrictive.

UE: User Equipment
eNB: eNodeB
EPC: Evolved Packet Core
MME: Mobility Management Entity
SGW: Serving Gateway

Claims (14)

delete delete delete delete delete delete delete An integrated circuit for controlling the operation of a transmitting terminal, comprising:
a receiving circuit for controlling reception of a system information broadcast from a base station;
a control circuit coupled to the receiving circuit;
The control circuit is
In response to the system information broadcast including information on the idle transmission radio resource pool, the information indicating radio resources available by the transmitting terminal in an idle state, direct link using the idle transmission radio resource pool Direct communication transmission with the receiving terminal through the connection,
Information on the temporary transmission radio resource pool without including information on the idle transmission radio resource pool - The information on the temporary transmission radio resource pool indicates radio resources usable by the transmitting terminal in an idle state or a connected state - In response to the system information broadcast comprising
integrated circuit.
9. The method of claim 8,
The temporary transmission radio resource pool is only that the transmitting terminal is allocated by the base station a dedicated radio resource usable for performing direct communication transmission, the transmitting terminal is the dedicated radio allocated to the transmitting terminal by the base station Transmitting that the transmitting terminal is not allowed to perform direct communication in the cell of the base station for the first time using resources to perform direct communication transmission, that the radio connection establishment procedure initiated by the transmitting terminal fails, or that the transmitting terminal is not permitted to perform direct communication in the cell of the base station Only any one of which the terminal is notified by the base station is usable by the transmitting terminal,
The dedicated radio resource is a radio resource selectable from an allocated transmission radio resource pool allocated to the transmitting terminal by the base station, or the dedicated radio resource is in response to a resource request from the transmitting terminal for direct communication transmission. A radio resource allocated to the transmitting terminal by the base station
integrated circuit.
10. The method of claim 9,
The dedicated radio resource starts in a subframe after the subframe in which the transmitting terminal transmits a scheduling assignment (SA) message
integrated circuit.
9. The method of claim 8,
The temporary transmission radio resource pool indicates a first set of radio resources available for performing direct communication transmission of a scheduling assignment to a receiving terminal through the direct link connection, and the scheduling assignment is the reception through the direct link connection. indicate a radio resource to be used by the transmitting terminal to perform subsequent direct communication transmission of data to the terminal;
The temporary transmission radio resource pool indicates a second set of radio resources available for performing direct communication transmission of data to a receiving terminal through a direct link connection.
integrated circuit.
9. The method of claim 8,
The system information broadcast is a system information block (SIB) type 18
integrated circuit.
9. The method of claim 8,
The control circuit is configured to use the temporary transmission radio resource pool for the transmitting terminal when the timer T300 for radio resource control (RRC) connection establishment expires.
integrated circuit.
9. The method of claim 8,
The system information broadcast indicates whether the temporary transmission radio resource pool is available when the transmitting terminal is within the coverage of a cell of the base station.
integrated circuit.

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